Process for gasifying fuels



Unite States Patent PROCESS FOR GA SIFYING FUELS Roman Rummel, Bruhl,Koln, Germany Application May 23, 1956, Serial No. 586,759

Claims priority, application Germany May 25, 1955 1 Claim. (Cl. 48-197)The present invention relates to an improved and efli- Ecient processfor the gasification of fuels and to an apparatus for carrying out thisprocess.

It is known to gasify finely divided, solid or liquid fuels byintroducing fuels and gasifying agents tangentially to the wall of thebody of a gas producer or to an imaginary circle of small diameter insuch a manner that the reactants in the body are caused to rotate aboutthe axis of the body, and withdrawing the resultant slag in moltencondition.

In these prior art processes, fuel is gasified at high temperature in awhirlpool of slag or in a cyclone-type fluidized bed of dust particles.The fuel is not gasified completely in this process so that part of thesensible heat of the unfinished gas is utilized for the gasificationreaction. Thus, an after reaction of the gas with the residual fuelcarried along therewith takes place on the path of the reactants throughthe body. It has been shown that, by the helical motion of the gascolumn in the body, the fuel particles suspended in the gas are thrownonto the wall where the gas is reduced. However, the gas no longerreacts in the core of the gas column, since the core is substantiallyfree of fuel. So the gas leaves the body of the gas producer with a highproportion of carbon dioxide and a low calorific value. Attempts havebeen made to lengthen the reaction path by modifying the equipment, e.g.by arranging tall bodies, but the problem can be solved only partiallyin this manner, since complete reduction of the gas cannot beaccomplished although, by friction, the helical motion of the gas columnis gradually slowed down on the long path through the body and part ofthe gas from the interior of the body undergoes further reaction. Inaddition, the Cooling of the gas to lower temperatures as a result ofthe tall body is detrimental to the after reaction of the gas. Thesensible heat dissipated through the wall of the body is withdrawn fromthe reduction process.

In accordance with the present invention, it has been found that thedisadvantages associated with the aforesaid prior art processes for thegasification of fuels in a body of a gas producer into which fuels andgasifying agents are introduced separately or jointly in such a mannerthat the fuels, gasifying agents and their reaction products rotateabout the axis of the body, can be avoidedv by deflecting the helicalpath of the produced unfinished gases and the non-gasified residual fuelparticles rotating about the axis of the body of the gas producer duringthe gasification reaction, into a direction substantially parallel tothe axis of the body, and distributing the fuel particles carried alongwith the gas all over the sectional area of the body. Thus, the reactionof fuels and gasifying agents takes place according to the invention notonly within a narrow Zone on the wall of the body, but all over thesectional area on a short path through the body. By deflecting thehelical gas stream into a direction parallel to the axis of the body,the fuel particles are prevented from being thrown onto the wall of thebody. This ensures a complete reaction between gas and fuel.

- the reaction or optimum heat utilization.

- Patented Nov. 17, 1959 The gas produced shows an optimum calorificvalue. The reaction space is fully utilized, so that the provision ofvery high equipment is not required. By concentrating the reactionprocess to a very small volume the loss of heat is slight and an optimumquantity of heat is supplied to the gasification process, whereby thecalorific value of the gas produced is further increased.

The deflection of the initially helical path into a parallel turbulentstream can be accomplished according to the invention for instance byarranging appropriate deflecting and orienting means in the body of agas producer. These deflecting and orienting means may be constructed invarious manners, which will be more fully explained below by way ofexamples. It is of advantage to provide deflecting and orienting meanswhich are adapted to secure a temporary increase of the flow velocityand, consequently, an increase of the relative velocity between the gasand fuel.

By reason of the low activity of the fuel particles which aresubstantially larger than the gas molecules, the relative velocitybetween fuels and gases is increased by the increase of velocity as wellas by the deflection and subsequent decrease of velocity of the gases.The increased relative velocity gives rise to a rapid exchange ofmaterial by promoting the removal of the reaction product and thefeeding of, and contact between, reactive gas constituents and fuelparticles.

The herein described various embodiments of the invention can be carriedout alone or in combination with each other, depending upon the mostfavorable course of Decisive for the choice of the specific embodimentto be applied in a given case is the reactivity of the fuel, the meltingpoint of the slag, the dependency of the toughness of the slag on thetemperature, and the desired composition of the gas to be produced. I

The application of the process according to the invention is not limitedto the gasification of fuels. The new process can also be used withadvantage for the combustion of fuels wherein the ash is withdrawn inmolten form. In the latter case, combustion agents, preferably air, areintroduced into the combustion chamber instead of gasifying agents. A

It is within the scope of the invention to carry out the process undersuperatmospheric pressure. The process of the invention and theapparatus adapted to carry out the new process will be more clearlyunderstood when read in conjunction with the accompanying diagrammaticdrawings which illustrate some of the various embodiments of theinvention by way of example and in which:

Fig. 1 is a side elevation, partially broken away, of a gasifier whereina slag bath rotates;

' Fig. 2 is a sectional view taken on the line 2-2 of the gasifier ofFig. 1.

At the lower section 1 of the body of the gas producer, the gasifyingagents and fuels are introduced into the slag bath, tangentially andobliquely toward the bottom of the gasifier, through inlet means 2 and 4and inlet means 3 and 5 respectively. By the fiow energy of thegasifying agents and fuels, the slag bath and all the materials abovethe slag (gasifying agents, fuel, reaction products thereof and slagdroplets) are caused to rotate about the axis of the body at high speedand the solid and liquid portions are thrown onto the wall of the bodyabove the level of the slag bath. The slag and the fuel taken up by theslag flow down the wall back into the slag bath, while the gases andresidual fuel stream up in a helical path. Slag runs off through theoverflow 6 at the rate slag is newly formed. The gases and fuelascending 0 in a rotary motion stream through the narrowed portion 7 ofthe body, their velocity being increased thereby.

The rotary current is deflected by the partition 8 in the neck 7 into adirection parallel to the axis of the body. Above the neck, the body iswidened again. Gas and fuel are distributed all over the sectional areaof the portion 9 of the body, their velocity being thereby decreased,and stream up in a uniform path parallel to the axis of the body towardsthe gas outlet (not shown in the drawing). On this path, the reactionbetween gas and fuels ceases. The non-gasified residual high-ash fuelcan be withdrawn from the gas and returned to the gasification process.

Fig. 3 is a side elevation, partially broken away, of a gasifier whereinthe velocity of the gases and the fuels carried along therewith in thebody is temporarily increased and the rotary motion of which isdeflected into a direction parallel to the axis of the body.

Fig. 4 is a sectional view taken on the line 44 of the gasifier of Fig.3.

The lower portion 10 of the body is constructed as a vortex chamber intowhich fuels and gasifying agents are introduced tangentially through thepipes 11. The slag formed runs off through the opening 12 at the bottomof the body. The gases and non-gasified fuelsrnoving up in a rotarytravel then flow through an annular narrowing 13 of the body and aredeflected by the partition Walls 14 arranged inside this narrowing intoa direction parallel to the axis of the body. The sectional area of theupper portion 15 of the body is widened as desired. Through thissection, the gases and fuels stream in uniform distribution at reducedvelocity towards the outlet of the body while the gasification reactionceases.

Fig. 5 is a side elevation, partially broken away, of that portion of agasifier wherein the stream of the gases and fuels is temporarilyincreased in velocity and defiected.

Fig. 6 is a sectional view taken on the line 6-6 of the gasifier of Fig.5.

The lower section communicates with the upper section 21 of the body viaopenings 22 of partition 22 through which the gases and fuels arepassed.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is, therefore, to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

I claim:

A process of gasifying fuels in a circular gasifying apparatus which hasseparate, distinct and interconnected lower and upper chambers separatedby a bafile partition which process comprises introducing the fuelparticles and the gasifying agents tangentially into the lower chamberof the gasifying apparatus to cause an upwardly directed whirling androtating motion of said fuel and agents along the wall of said chamber,the velocity of said fuel particles and gasifying agents remainingsubstantially uniform during travel through the lower chamber,deflecting the mixture of the produced gas and the incompletelygasifiedfuel particles rotating along said wall during the:

gasitication from the helical path to a straight line vertical path whenthe mixture passes from the lower chamber and through the bafilepartition, simultaneously increasingv the velocity of the mixture as itenters and passes through the bafile partition, maintaining saidstraight line path as the mixture passes into and through the upperchamber of the gasification apparatus, simultaneously decreasing thevelocity of said mixture as it passes into the upper chamber, theincompletely gasified fuel particles of said mixture being distributedduring the further gasification uniformly and equally over the entiresectional area of said upper chamber thereby completing thegasification, and withdrawing the produced gas from said upper chamberof the gasification apparatus.

References Cited in the file of this patent UNITED STATES PATENTS1,083,683 Hirt Jan. 6, 1914 2,388,348 Stimson Nov. 6, 1945 2,516,141Newman July 25, 1950 2,558,746 Gaucher July 3, 1951 2,644,745 HemmingerJuly 7, 1953 2,655,443 Moore Oct. 13, 1953 2,702,743 Totzek Feb. 22,1955 2,703,275 Elliott Mar. 1, 1955

